Rugged up against the bone-chilling cold in the Scottish capital's visually and acoustically impressive St Mary's Cathedral, the full-house audience seem aware they are in for something special. The two-part concert begins with a clear as ice spoken introduction from esteemed New York-based jazz singer and previous collaborator with Tommy Smith and the Scottish National Jazz Orchestra (SNJO), Kurt Elling. With appropriate gravitas, Elling explains that this concert will be "a modern meditation on the delirium that visits us at this season," and that it would be no regular jazz gig.

Appetites thus whetted, the focus shifts to tonight's other soloist: composer, SNJO leader and jazz tenor saxophonist Tommy Smith who, processing up the central aisle, scatters mellifluous wisps of saxophone figures, whilst Cappella Nova, Scotland's foremost vocal group, arrive via the side-aisles, five each side, intoning over a background drone. A marriage of theatre and thoughtfulness, from the outset Smith confidently emphasizes his own central role in this concert.

Thus begins Spirit of Light, Smith's first composition since his 2016 classical large orchestral work, Modern Jacobite. Known mainly for his virtuosity in saxophone and jazz composition, Smith has however composed classical music since the 1990s when he also collaborated with the late Scottish poet Edwin Morgan.

In Spirit of Light, Smith once again sets his music to poetry: eleven poems (in English) and one Kyrie (in English and Latin), the poets ranging widely this time, to include former Scottish Makar Liz Lochead (whose poem 'Spirit of Light' was commissioned by Smith for this concert), Norman MacCaig, Rainer Maria Rilke, Franz Wright and St Francis of Assisi. The common thread seems to be the poets' thoughtfulness and humanitarianism even in harsh circumstances.

Smith's music likewise comes from a place of deep thought and maturity, with a wide range of musical styles and influences evident, the playing mostly at moderate tempo and volume, so the complexity is both made accessible to the audience and capitalizes on the cathedral's resonant acoustics. His sparing phrases and saxophone's sighs, floating and expiring high in the rafters, show a delicacy and restraint in keeping with the concert's message. Smith pares down the SNJO to only 7 members (three trumpets, two trombones, double bass and drums) but augments it with flute, bass clarinet, tuba, harp, tympani, percussion, and cathedral organ. There is however no excess: each note and word count.

Meanwhile Elling's mahogany tones further enrich the message of each poem, his crystal clear diction allowing not a word to be missed. The supporting orchestra are exemplary in their ensemble support, with irrepressible Alyn Cosker on drums only briefly upping the ante in Robert Frost's 'Stopping by Woods on a Snowy Evening'. The Cappella Nova, experienced as they are in singing some of the most interesting music in modern times, such as John Tavener and James MacMillan, give sensitive support throughout.

To this reviewer, the overall effect is that of a highly personal, important message to the audience. Tonight's is not so much a concert, as rather 'an event', both in terms of the wide range of performance elements at work and also as it constitutes a significant step in Smith's continuing development as a thinker and composer. Spirit of Light is a major work, and this reviewer now sees Smith in addition to his other many achievements, as a major classical composer.

Finally, this work feels very Scottish but also gazes afar, it looks to the past but also with hope, to the future. It is a work for our time yet it is also feels timeless. Such richness deserves to be experienced widely and one even wonders: could Spirit of Light become a regular winter event?